1. Field of the Invention
This invention relates to a downhole connection for use in a subterranean wellbore to couple a wellbore tool to a workstring for manipulation and conveyance of the wellbore tool.
2. Description of the Prior Art
Prior art downhole connections have been used to releasably couple a workstring to a wellbore tool as the wellbore tool is disposed downhole inside of a wellbore. Once releasably coupled, the workstring may be used for manipulation and conveyance of the wellbore too. Typically, prior art downhole connections consisted of a retrieving head disposed on the lower end of the workstring, with the retrieving head including a box connector that mates with a pin connector included on the upper end of the wellbore tool.
To couple a typical prior art retrieving head with a wellbore tool, the prior art retrieving head is lowered into the wellbore and over the upper end of the wellbore tool. As the retrieving head is lowered over the upper end of the wellbore tool, the retrieving head is rotated with an engagement rotation to interlock the retrieving head box connector with the wellbore tool pin connector in releasable mating engagement so that torque and upward forces can be transmitted from the workstring, through the retrieving head, and to the wellbore tool. Typically, the engagement rotation to interlock the box connector to the pin connector is right-hand rotation, which automatically occurs as the box connector is lowered over the pin connector.
To uncouple a prior art retrieving head box connector from a wellbore tool pin connector, the retrieving head is lifted while being rotated with a disengagement rotation which is an opposite rotation from the rotation used to interlock the retrieving head box connector with the wellbore tool pin connector. Typically, the disengagement rotation is left-hand rotation, which requires left-hand torque to be applied to the workstring.
A problem arises since workstrings are typically comprised of threaded tubular members which are made up, or connected, by right-hand rotation, and broken down, or separated, by left-hand rotation. So whenever left-hand torque was applied to the workstring to impart left-hand rotation to uncouple prior art retrieving heads from wellbore tool pin connectors, there was always a risk of the threaded tubular members in the workstring unscrewing and being left in the wellbore.